(R,S) .alpha.-cyano-3-phenoxy-benzyl acetate, which is a racemic mixture, is known.
European Patent Application No. 84300024.1 discloses a method for biologically preparing optically active (S) .alpha.-cyano-3- phenoxy-benzyl alcohol, which is the alcohol moiety of certain pyrethroids, by reacting an ester of racemic (R,S) .alpha.-cyano-3-phenoxy-benzyl alcohol with an esterase wherein the ester of (S) .alpha.-cyano-3-phenoxy-benzyl alcohol is predominantly hydrolyzed thereby permitting optical resolution of the (S)-isomer alcohol from the ester of its antipode. Thus, there is provided in the art a biological method capable of producing (R) .alpha.-cyano-3-phenoxy-benzyl acetate. Until Applicants' invention, however, there has existed no known method for producing the (S)-isomer of .alpha.-cyano-3-phenoxy-benzyl acetate insofar as Applicants are aware.